// duplicates the item and returns a new object
// oItem - item to copy
// oTargetInventory - create item in this object's inventory. If this parameter
//                    is not valid, the item will be created in oItem's location
// bCopyVars - copy the local variables from the old item to the new one
// * returns the new item
// * returns OBJECT_INVALID for non-items.
// * can only copy empty item containers. will return OBJECT_INVALID if oItem contains
//   other items.
// * if it is possible to merge this item with any others in the target location, 
//   then it will do so and return the merged object.
object CopyItem(object oItem, object oTargetInventory=OBJECT_INVALID, int bCopyVars=FALSE);